A patient with a suspected closed head injury has bloody nasal drainage. Which observation indicates a cerebrospinal fluid leak?

• A. Halo sign on the nasal drip pad
• B. Decreased blood pressure and urinary output
• C. A positive reading for glucose on a test-tape strip
• D. Clear nasal drainage along with the bloody discharge

Answer: (A)

CSF leaks after head injury often present as clear, watery nasal drainage, and the hallmark bedside indicator is a halo sign on the drainage pad. When CSF leaks out and mixes with blood, the clear fluid separates around the central blood stain, forming a ring or halo. CSF does contain glucose, so a glucose test can support the finding, but the halo sign on the pad is the most specific clue that CSF is leaking from the nose.

Other observations like low blood pressure and reduced urine output aren’t specific to CSF leakage and can reflect other trauma-related issues. A glucose test alone can be helpful but isn’t as definitive as the halo sign. Clear drainage with blood could be simply epistaxis unless a halo is present, which points to CSF leaking. If a CSF leak is suspected, notify the care team and take appropriate precautions to reduce infection risk and avoid actions that could worsen the leak.